Dissociation constant of the norepinephrine receptor complex in normotensive and hypertensive rats

R. B. Strecker, W. C. Hubbard, A. M. Michelakis

Research output: Contribution to journalArticle

Abstract

Previous reports have suggested that smooth muscle obtained from the thoracic aorta of spontaneously hypertensive rats is less responsive to vasoconstrictive agents than that obtained from normotensive rats. The present study was undertaken to determine whether the responsiveness of aortic muscles from normotensive and spontaneously hypertensive rats correlates with a difference in the affinity of the adrenergic receptors for norepinephrine and whether antihypertensive therapy alters the affinity of the adrenergic receptors for norepinephrine. The affinity of the adrenergic receptors for norepinephrine was determined by computing the dissociation constant of the norepinephrine receptor complex (K(DR)). The values computed for K(DR) in aortic muscles from normotensive and spontaneously hypertensive rats that had received no antihypertensive therapy were 1.07 x 10-7M and 1.17 x 10-7M, respectively. The values computed for K(DR) in aortic muscles from normotensive and spontaneously hypertensive rats that had received antihypertensive therapy were 1.38 x 10-7M and 1.29 x 10-7M, respectively. The differences in these values for K(DR) are not significant. These results indicate that the difference in the contractility of aortic muscles from normotensive and spontaneously hypertensive rats is not related to an alteration in the affinity of the adrenergic receptors for norepinephrine and that the affinity of the adrenergic receptors for norepinephrine is not altered by antihypertensive therapy. Thus, it appears that the etiology of hypertension cannot be directly correlated with a difference in the affinity of the adrenergic receptors for norepinephrine.

Original languageEnglish (US)
Pages (from-to)658-663
Number of pages6
JournalCirculation research
Volume37
Issue number5
DOIs
StatePublished - Jan 1 1975

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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